Nissan's owners manual says not to leave the battery at low or zero charge for more than 14 days. That's on page EV-24 of the 2014 owners manual.
Though not probable, it could be possible that a car could have been driven to turtle and then left uncharged for 6 months or so. I don't know what happens to a leaf at an auction site, but I can imagine it could happen.
I don't know if a leaf battery could be so deeply discharged that the battery pack could reverse polarity, but I do know that some types of rechargable batteries can reverse polarity if left totally discharged.
Perhaps this is more of a hypothetical issue than real issue or maybe it's like winning the PowerBall but in reverse.
On a different note, my battery SOH has increased from 85% in April to 89% now. HX has increased from 83.22% to 88.65% over the same period of time.
I charge it on an L1 evse to 100% every night and drive it about 40 to 50 miles a day. I pretty much just make sure I drive it every day or unplug it if I'm not going to drive on a specific day.
It's a 2014 SV, and the price was really good.
if I can get 6 years out of it before the battery pack is toasted or one of our chuck holes breaks (aka road canyons) break something too expensive to fix, I'll be really happy with the car.
It will be interesting to see how the battery pack holds up over time.